Char.ConvertFromUtf32(Int32) Method

public:
 static System::String ^ ConvertFromUtf32(int utf32);

public static string ConvertFromUtf32(int utf32);

static member ConvertFromUtf32 : int -> string

Public Shared Function ConvertFromUtf32 (utf32 As Integer) As String

Parameters

Returns

A string consisting of one Char object or a surrogate pair of Char objects equivalent to the code point specified by the utf32 parameter.

Exceptions

Examples

The following code example demonstrates the ConvertToUtf32 and ConvertFromUtf32 methods.

// This example demonstrates the Char.ConvertFromUtf32() method
// and Char.ConvertToUtf32() overloads.
using System;

class Sample
{
 public static void Main()
 {
 int letterA = 0x0041; //U+00041 = LATIN CAPITAL LETTER A
 int music = 0x1D161; //U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE
 string s1;
 string comment = "Create a UTF-16 encoded string from a code point.";
 string comment1b = "Create a code point from a UTF-16 encoded string.";
 string comment2b = "Create a code point from a surrogate pair at a certain position in a string.";
 string comment2c = "Create a code point from a high surrogate and a low surrogate code point.";

// Convert code point U+0041 to UTF-16. The UTF-16 equivalent of
// U+0041 is a Char with hexadecimal value 0041.

 Console.WriteLine(comment);
 s1 = Char.ConvertFromUtf32(letterA);
 Console.Write(" 1a) 0x{0:X} => ", letterA);
 Show(s1);
 Console.WriteLine();

// Convert the lone UTF-16 character to a code point.

 Console.WriteLine(comment1b);
 letterA = Char.ConvertToUtf32(s1, 0);
 Console.Write(" 1b) ");
 Show(s1);
 Console.WriteLine(" => 0x{0:X}", letterA);
 Console.WriteLine();

// -------------------------------------------------------------------

// Convert the code point U+1D161 to UTF-16. The UTF-16 equivalent of
// U+1D161 is a surrogate pair with hexadecimal values D834 and DD61.

 Console.WriteLine(comment);
 s1 = Char.ConvertFromUtf32(music);
 Console.Write(" 2a) 0x{0:X} => ", music);
 Show(s1);
 Console.WriteLine();

// Convert the surrogate pair in the string at index position
// zero to a code point.

 Console.WriteLine(comment2b);
 music = Char.ConvertToUtf32(s1, 0);
 Console.Write(" 2b) ");
 Show(s1);
 Console.WriteLine(" => 0x{0:X}", music);

// Convert the high and low characters in the surrogate pair into a code point.

 Console.WriteLine(comment2c);
 music = Char.ConvertToUtf32(s1[0], s1[1]);
 Console.Write(" 2c) ");
 Show(s1);
 Console.WriteLine(" => 0x{0:X}", music);
 }

 private static void Show(string s)
 {
 for (int x = 0; x < s.Length; x++)
 {
 Console.Write("0x{0:X}{1}",
 (int)s[x],
 ((x == s.Length-1)? String.Empty : ", "));
 }
 }
}
/*
This example produces the following results:

Create a UTF-16 encoded string from a code point.
 1a) 0x41 => 0x41
Create a code point from a UTF-16 encoded string.
 1b) 0x41 => 0x41

Create a UTF-16 encoded string from a code point.
 2a) 0x1D161 => 0xD834, 0xDD61
Create a code point from a surrogate pair at a certain position in a string.
 2b) 0xD834, 0xDD61 => 0x1D161
Create a code point from a high surrogate and a low surrogate code point.
 2c) 0xD834, 0xDD61 => 0x1D161

*/

open System

let show (s: string) =
 for x = 0 to s.Length - 1 do
 printf $"""0x{int s[x]:X}{if x = s.Length - 1 then String.Empty else ", "}""" 

[<EntryPoint>]
let main _ =
 let letterA = 0x0041 //U+00041 = LATIN CAPITAL LETTER A
 let music = 0x1D161 //U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE
 let comment = "Create a UTF-16 encoded string from a code point."
 let comment1b = "Create a code point from a UTF-16 encoded string."
 let comment2b = "Create a code point from a surrogate pair at a certain position in a string."
 let comment2c = "Create a code point from a high surrogate and a low surrogate code point."

// Convert code point U+0041 to UTF-16. The UTF-16 equivalent of
// U+0041 is a Char with hexadecimal value 0041.

 printfn $"{comment}"
 let s1 = Char.ConvertFromUtf32 letterA
 printf $" 1a) 0x{letterA:X} => "
 show s1
 printfn ""

// Convert the lone UTF-16 character to a code point.

 printfn $"{comment1b}"
 let letterA = Char.ConvertToUtf32(s1, 0)
 printf " 1b) "
 show s1
 printfn $" => 0x{letterA:X}"
 printfn ""

// -------------------------------------------------------------------

// Convert the code point U+1D161 to UTF-16. The UTF-16 equivalent of
// U+1D161 is a surrogate pair with hexadecimal values D834 and DD61.

 printfn $"{comment}"
 let s1 = Char.ConvertFromUtf32 music
 printf $" 2a) 0x{music:X} => "
 show s1
 printfn ""

// Convert the surrogate pair in the string at index position
// zero to a code point.

 printfn $"{comment2b}" 
 let music = Char.ConvertToUtf32(s1, 0)
 printf " 2b) "
 show s1
 printfn $" => 0x{music:X}"

// Convert the high and low characters in the surrogate pair into a code point.

 printfn $"{comment2c}"
 let music = Char.ConvertToUtf32(s1[0], s1[1])
 printf " 2c) "
 show s1
 printfn $" => 0x{music:X}"

 0

// This example produces the following results:
//
// Create a UTF-16 encoded string from a code point.
// 1a) 0x41 => 0x41
// Create a code point from a UTF-16 encoded string.
// 1b) 0x41 => 0x41
//
// Create a UTF-16 encoded string from a code point.
// 2a) 0x1D161 => 0xD834, 0xDD61
// Create a code point from a surrogate pair at a certain position in a string.
// 2b) 0xD834, 0xDD61 => 0x1D161
// Create a code point from a high surrogate and a low surrogate code point.
// 2c) 0xD834, 0xDD61 => 0x1D161

Class Sample
 Public Shared Sub Main()
 Dim letterA As Integer = &H41 'U+00041 = LATIN CAPITAL LETTER A
 Dim music As Integer = &H1D161 'U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE
 Dim s1 As String
 Dim comment As String = "Create a UTF-16 encoded string from a code point."
 Dim comment1b As String = "Create a code point from a UTF-16 encoded string."
 Dim comment2b As String = "Create a code point from a surrogate pair at a certain position in a string."
 Dim comment2c As String = "Create a code point from a high surrogate and a low surrogate code point."
 
 ' Convert code point U+0041 to UTF-16. The UTF-16 equivalent of 
 ' U+0041 is a Char with hexadecimal value 0041.

 Console.WriteLine(comment)
 s1 = [Char].ConvertFromUtf32(letterA)
 Console.Write(" 1a) 0x{0:X} => ", letterA)
 Show(s1)
 Console.WriteLine()
 
 ' Convert the lone UTF-16 character to a code point.

 Console.WriteLine(comment1b)
 letterA = [Char].ConvertToUtf32(s1, 0)
 Console.Write(" 1b) ")
 Show(s1)
 Console.WriteLine(" => 0x{0:X}", letterA)
 Console.WriteLine()
 
 ' -------------------------------------------------------------------

 ' Convert the code point U+1D161 to UTF-16. The UTF-16 equivalent of 
 ' U+1D161 is a surrogate pair with hexadecimal values D834 and DD61.

 Console.WriteLine(comment)
 s1 = [Char].ConvertFromUtf32(music)
 Console.Write(" 2a) 0x{0:X} => ", music)
 Show(s1)
 Console.WriteLine()
 
 ' Convert the surrogate pair in the string at index position 
 ' zero to a code point.

 Console.WriteLine(comment2b)
 music = [Char].ConvertToUtf32(s1, 0)
 Console.Write(" 2b) ")
 Show(s1)
 Console.WriteLine(" => 0x{0:X}", music)
 
 ' Convert the high and low characters in the surrogate pair into a code point.

 Console.WriteLine(comment2c)
 music = [Char].ConvertToUtf32(s1.Chars(0), s1.Chars(1))
 Console.Write(" 2c) ")
 Show(s1)
 Console.WriteLine(" => 0x{0:X}", music)
 End Sub
 
 Private Shared Sub Show(s As String)
 Dim x As Integer
 If s.Length = 0 Then Exit Sub
 For x = 0 To s.Length - 1
 Console.Write("0x{0:X}{1}", _
 AscW(s.Chars(x)), _
 IIf(x = s.Length - 1, [String].Empty, ", "))
 Next 
 End Sub 
End Class 
'
'This example produces the following results:
'
'Create a UTF-16 encoded string from a code point.
' 1a) 0x41 => 0x41
'Create a code point from a UTF-16 encoded string.
' 1b) 0x41 => 0x41
'
'Create a UTF-16 encoded string from a code point.
' 2a) 0x1D161 => 0xD834, 0xDD61
'Create a code point from a surrogate pair at a certain position in a string.
' 2b) 0xD834, 0xDD61 => 0x1D161
'Create a code point from a high surrogate and a low surrogate code point.
' 2c) 0xD834, 0xDD61 => 0x1D161
'

Remarks

Use this method to convert a 21-bit Unicode code point to a UTF-16 encoded string before testing the string with methods such as IsLowSurrogate(Char) and IsHighSurrogate(Char).

A valid code point outside the Basic Multilingual Plane (BMP) always yields a valid surrogate pair. However, a valid code point within the BMP might not yield a valid result according to the Unicode standard because no linguistic processing is used in the conversion. For that reason, use the System.Text.UTF32Encoding class to convert bulk UTF-32 data into bulk UTF-16 data.

See also

• Rune
• ConvertToUtf32(Char, Char)
• UTF32Encoding